Perception and Attention Flashcards
can be defined as the way information or any external stimulus is identified, organized and interpreted.
Perception
The ability to focus on specific information, maintaining the focus and being able to shift it at will to another is called
Attention.
Perception is the process of perceiving the sensory input and further interpreting it into
meaningful patterns.
Sensation + meaning=
Perception
Through the process of _________ we acquire sensory experience and through the process of perception we interpret and respond to such stimulations.
sensation
Perception consists of three components:
The perceiver, the target, the situation
She/he is a person who becomes aware about something in the environment and further comes to a final understanding. There are 3 factors that can influence his or her perceptions: Experience, motivational state and finally emotional state.
The Perceiver
: This is the person who is being perceived or judged. “Ambiguity or lack of in- formation about a target leads to a greater need for interpretation and addition.”
The Target
also greatly influences perceptions because different situations may call for additional information about the target. When a perceiver focuses on something he or she may start giving meaning to the events around them, for detailed understanding.
The Situation
: The world is full of stimuli that can attract attention through various senses. The environmental stimulus is everything in the environment that has the potential to be perceived.
The Environmental Stimulus
: The attended stimulus is the specific object in the environment on which attention is focused.
The Attended Stimulus
: This involves light actually passing through the cornea and pupil and onto the lens of the eye. The cornea helps focus the light as it enters the eye, and the and onto the lenstrols the size of the pupils in order to determine how much light to let in The cornea and lens act together to project an inverted image onto the retina.
The Image on the Retina
: The image on the retina is then transformed into electrical signals in a pro. cess known as transduction. This allows the visual messages to be transmitted to the brain to be interpreted.
Transduction
: The electrical signals then undergo neural processing. The path fol. lowed by a particular signal depends on what type of signal it is (i.e. an auditory signal or a visual signal).
Neural Processing
: In this step of the process, you perceive the stimulus object in the environment. It is at this point that you become consciously aware of the stimulus.
Perception
: Perception doesn’t just involve becoming consciously aware of the stimuli. It is also necessary for the brain to categorize and interpret what you are sensing. The ability to interpret and give meaning to the object is the next step.
Recognition
: The action phase of perception involves some type of motor activity that occurs in response to the perceived and recognized stimulus. This might involve a major action, like running toward a person in distress, or something as subtle as blinking your eyes in response to a puff of dust blowing through the air.
Action
According to ___________________, this apparent movement happens because our minds fill in missing information. This belief that the whole is greater than the sum of the individual parts led to the discovery of several different phenomena that occur during perception.
Gestalt psychology
Rapid sequences of perceptual events, such as rows of flashing lights, create the illusion of motion even when there is none. Motion pictures are based on this principle, with a series of still images appearing in rapid succession to form a seamless visual experience.
the phi phenomenon.
suggests that things similar things tend to appear grouped together. Grouping can occur in both visual and auditory stimuli.
Law of Similarity
German term meaning “good figure.” is sometimes referred to as the law of good figure or the law of simplicity. This law holds that objects in the en- vironment are seen in a way that makes them appear as simple as possible.
Law of Pragnanz
things that are near each other seem to be grouped together. In the above image, the circles on the left appear to be part of one grouping while those on the right appear to be part of another. Because the objects are close to each other, we group them together.
Law of Proximity
Points that are connected by straight or curving lines are seen in as by that follows the smoothest path. Rather than seeing separate lines and angles, lines are seen as belonging together.
Law of Continuity
Things are grouped together if they seem to complete some entity. Our brains often ignore contradictory information and fill in gaps in information. In the image above, you probably see the shapes of a circle and rectangle because your brain fills in the missing gaps in order to create a meaningful image.
Law of Closure
It refers to the errors in judgment made by the perceiver as a result of bias, easy access to data or ignorance of important information. It views perception as a function of physical properties of the object and characteristics of the perceiver as well.
Perceptual Set Theory
External Factors Affecting Perceptual Set Include:
Frequency, Stimulus Intensity, Stimulus Magnitude, Social Consequences, Context
: It refers to rate of occurrence of objects in a specific category. This will help us on focusing our attention to that specific object, which had occurred number of times. Repeated external stimulus gathers more attention than a single one, therefore stating the frequency principle. Repetition is one of the most regularly used techniques in advertising and is the most common way of attracting the people’s attention. results in making people aware of the stimulus.
Frequency
: If other stimulus is comparable, more intense stimulus attracts more attention than a subtle one. For example, a loud siren gets more attention than a faint one. Thus the sound plays an important role in perception of an object.
Stimulus Intensity
: It also plays an important role in attracting our attention. For example, a large advertising board attracts more attention than the small one. Therefore the size of the object affects our perception.
Stimulus Magnitude
: Categories commonly used by others seem more “ready”, e.g. inambiguous situations, this can be confirmed by such social phenomena as stereotyping, conformity, or diffusion of responsibility.
Social Consequences
Minturn and Bruner, 1951 illustrated how of alphabets and numbers plays a role in perception. For instance, exposing the subject to a vague number ‘9’ in the conten of letter and numbers will yield different responses. In case of numbers, it will carry significance, however, in case of letters, it will prove insignificant as one expects others letter to follow than a number.
Context
Internal Factors affecting the perceiver while perceiving the categories are:
Motivation, Emotion, Expectation, Culture
6 types of motivational determinants of perception such as:
Bodily needs (physiological needs).
Reward and punishment.
Emotional connotation.
Individual values.
Personality.
The value of objects.
influences the likelihood and nature of our perception about the objects and events around us.
motivation
in various investigation robust effects of emotion on perception are observed. The term ‘percep- tal defense’ is used to connote the same. It refers to delay in conscious recognition of unpleas ant emotions than neutral emotions. In an investigation, exposed the subjects to eleven neutral (broom”, “glass”, “apple”) and eleven taboo words (“rape”, “whore”, “penis”). The results revealed higher reaction time for taboo words in spite of greater exposure duration than neutral words. The results were a true example of perceptual defense which was operating to avoid evoking of unpleasant emotions.
Emotion
Prefers to the idea that what we perceive is to some extent, influenced by what we expect.
Expectation
Strong cross cultural differences are believed to interfere in perceptual processes. The background history and culture emerge as strong factors influencing the perceptual set. The connotation of any term changes in reference to the culture where it is being used. For instance, taboo word “Se would create less offence in America than a Muslim orthodox country.
Culture
refers to unique perceptual experiences in which information is received from the “real” external stimuli. This information further leads to an incorrect perception or a false impres sion, leading to stimulation from the objects or events. It is a constant error in visual perception. Therefore it is a wrong or false perception.
Illusion
Causes of Illusion
Similarity, Expectancy, Subjective factor
Identify if Hallucination or Illusion: is kind of a false or wrong perception
Illusion
Identify if Hallucination or Illusion: are caused by internal stimulations, no external stimulus is present.
Hallucinations
Identify if Hallucination or Illusion: is generally referred to as false perception.
Hallucination
Identify if Hallucination or Illusion: consist of an external stimulus
Illusion
Hallucination or Illusion: is almost common and is generally universal
Illusion
Hallucination or Illusion: Normal persons can also suffer from it.
Illusion
Hallucination or Illusion: Similar situation produce the same type of __________ in most people.
illusion
Hallucinations or Illusions: is related to one’s personal experiences
Hallucination
Hallucinations or Illusions: are limited to mentally ill persons.
Hallucinations
Hallucinations or Illusions: Individual differences play a role with regard to hallucination. It is also seen that same individual may experience different hallucinations on different occasions also.
Hallucinations
: It indicates that two objects that appear to be equal in size and shape may be subject to higher degree of illusion. For instance, a long leaf as a lizard on the floor.
Similarity
: It refers to the phenomena that when we are expecting something then every thing seems to be fall similar to the expectant object. For example, while waithing for an empty auto rickshaw, all autos at a distant appear to be empty. Another example would be that, while searching for your lost jewelry all other glittering objects will be mistaken for the one which you are searching.
Expectancy
: Sometimes our habits and familiarity towards objects can cause illusion. For example cross two fingers of your hand, try and feel a marble with the crossed fingers you may see to feel one marble as separated into two.
Subjective Factor
was discovered by Mario Ponzo, an Italian psychologist. is one among a number of illusions where a central aspect of a simple line image-e.g. the length, straightness, or parallelism of lines-appears distorted by other aspects of the image-e.g. other background/foreground lines, or other intersecting shapes. These are sometimes called ‘geometrical-optical illusions’.
The Ponzo Illusion
was created by Johann Karl Friedrich Zöllner, a German astrophysicist with a keen interest in optical illusions. It is one among a number of illusions where a central aspect of a simple line image - e.g. the length, straightness, or parallelism of lines - appears distorted in virtue of other aspects of the image - e.g. other background/foreground lines, or other intersecting shapes. These are sometimes called ‘geometrical-optical illusions’.
The Zöllner Illusion
depth perception plays an important role in how we see the moon at the horizon versus high in the sky. This theory is centered on the idea that when you view the moon at the horizon, you are seeing it in the presence of depth cues such as trees, mountains, and other scenery. When the moon has moved higher into the sky, those depth cues disappear. Because of this, the apparent distance theory suggests, we tend to see the moon as further away on the horizon than we see it when it elevated in the sky.
moon illusion
This explanation focuses instead on the visual angle of the moon in comparison to surrounding objects. When the moon is on the horizon and surrounded by smaller objects, it appears larger. At its zenith, the moon appears much smaller because it is surrounded by the large expanse of the sky.
Angular Size-Contrast Theory
While these are just two of the most prominent theories, there have been many different explanations proposed over the years and no true consensus exists. Part of the reason is that there are a number of factors that appear to influence the occurrence of this optical phenomenon, including:
* Color: When the moon appears red (due to smoke or dust in the air), it appears larger.
Those who live in rural areas may notice this effect during harvest season when the horizon is often clouded with dust and other particulates.
* Atmospheric Perspective: When it is hazy or smoky outside, the moon appears larger on the horizon. After a forest fire or on a day when it seems particularly smoggy, you might notice that the moon illusion seems more pronounced.
* Visual Factors: Convergence of the eyes when viewing things on the horizon also causes objects to appear larger.
Factors that Influence the Illusion
is named after its creator, Franz Carl Müller-Lyer, a German psychia trist and sociologist. The Müller-Lyer Illusion is one among a number of illusions where a central aspect of a simple line image e.g. the length, straightness, or parallelism of lines appears distorted in virtue of other aspects of the image e.g. other background/foreground lines, or other intersecting shapes. These are sometimes called ‘geometrical-optical illusions’.
The Müller-Lyer Illusion
can be defined as the process of processing information into a meaningful whole.
perceptual processing
is a system in which people take in individual elements of a stimulus and then combine them into a unified perception.
Bottom-up processing
is the use of pre-existing knowledge to organize individual features into a unified whole.
Top-down processing
is the visual ability to perceive the world in three dimensions (3D) and the dis- tance of an object. Depth sensation is the corresponding term for animals, since although it is known that animals can sense the distance of an object (because of their ability to move accurately or to respond consistently, according to that distance), it is not known whether they “perceive” it in the same subjective way that humans do.
Depth perception
include size: distant objects subtend smaller visual angles than near objects, grain, size, and motion parallax.
Monocular cues
When an observer moves, the apparent relative motion of several stationary objects against a background gives hints about their relative distance. If information about the direction and velocity of movement is known, motion parallax can provide absolute depth information. This effect can be seen clearly when driving in a car.
Motion Parallax
When an object moves toward the observer, the retinal projection of an object expands over a period of time, which leads to the perception of movement in a line toward the observer. Anoth- er name for this phenomenon is depth from optical expansion. The dynamic stimulus change enables the observer not only to see the object as moving, but to perceive the distance of the moving object.
Depth from Motion
The effect also occurs when the rotating object is solid, provided that the projected shadow consists of lines which have definite corners or endpoints, and that these lines change in both length and orientation during the rotation. If a stationary rigid figure (for example, a wire cube) is placed in front of a point source of light so that its shadow falls on a translucent screen, an observer on the other side of the screen will see a two-dimensional pattern of lines. But if the cube rotates, the visual system will extract the necessary information for perception of the third dimension from the movements of the lines, and a cube is seen.
Kinetic Depth Effect
The property of parallel lines converging in the distance, at infinity, allows us to reconstruct the relative distance of two parts of an object, or of landscape features. An example would be standing on a straight road, looking down the road, and noticing the road narrows as it goes off in the distance.
Perspective
If two objects are known to be the same size (e.g., two trees) but their absolute size is unknown, ——– size cues can provide information about the relative depth of the two objects. If one sub- tends a larger visual angle on the retina than the other, the object which subtends the larger visual angle appears closer.
Relative Size
Since the visual angle of an object projected onto the retina decreases with distance, this information can be combined with previous knowledge of the object’s size to determine the absolute depth of the object. For example, people are generally familiar with the size of an average automobile. This prior knowledge can be combined with information about the angle it subtends on the retina to determine the absolute depth of an automobile in a scene.
Familiar Size
Even if the actual size of the object is unknown and there is only one object visible, a smaller object seems further away than a large object that is presented at the same location.
Absolute Size
Due to light scattering by the atmosphere, objects that are a great distance away have lower luminance contrast and lower color saturation. Due to this, images seem hazy the farther they are away from a person’s point of view. In computer graphics, this is often called “distance fog”. The foreground has high contrast; the background has a low contrast. Objects differing only in their contrast with a background appear to be at different depths. The colors of distant objects are also shifted toward the blue end of the spectrum (e.g., distant mountains). Some painters, notably Cézanne, employ “warm” pigments (red, yellow and orange) to bring features forward towards the viewer, and “cool” ones (blue, violet, and blue-green) to indicate the part of a form that curves away from the picture plane.
Aerial Perspective
This is an oculomotor cue for depth perception. When we try to focus on faraway objects, the ciliary muscles stretch the eye lens, making it thinner, and hence changing the focal length. The kin- esthetic sensations of the contracting and relaxing ciliary muscles (intraocular muscles) are sent to the visual cortex where it is used for interpreting distance/depth.
Accommodation
(also referred to as interposition) happens when near surfaces overlap far surfaces. If one object partially blocks the view of another object, humans perceive it as closer. However, this information only allows the observer to create a “ranking” of relative nearness. The presence of monocular ambient occlusions consists of the object’s texture and geometry. These phenomena are able to reduce the depth perception latency both in natural and artificial stimuli
Occultation
At the outer extremes of the visual field, parallel lines become curved, as in a photo taken through a fish-eye lens. This effect, although it is usually eliminated from both art and photos by the cropping or framing of a picture, greatly enhances the viewer’s sense of being positioned within a real, three-dimensional space. (Classical perspective has no use for this so-called “distortion,” although in fact the “distortions” strictly obey optical laws and provide perfectly valid visual in- formation, just as classical perspective does for the part of the field of vision that falls within its frame).
Curvilinear Perspective
Fine details on nearby objects can be seen clearly, whereas such details are not visible on faraway objects. Texture gradients are grains of an item. For example, on a long gravel road, the gravel near the observer can be clearly seen of shape, size, and color. In the distance, the road’s texture cannot be clearly differentiated.
Texture Gradient
The way that light falls on an object and reflects off its surfaces, and the shadows that are cast by objects provide an effective cue for the brain to determine the shape of objects and their position in space.
Lighting and Shading
Selective image blurring is very commonly used in photographic and video for establishing the impression of depth. This can act as a monocular cue even when all other cues are removed. It may contribute to the depth perception in natural retinal images because the depth of focus of the human eye is limited. In addition, there are several depth estimation algorithms based on defocus and blurring. Some jumping spiders are known to use image defocus to judge depth.
Defocus Blur
Animals that have their eyes placed frontally can also use information derived from the different projection of objects onto each retina to judge depth. By using two images of the same scene ob- tained from slightly different angles, it is possible to triangulate the distance to an object with a one object partially blocks the view of another object, humans perceive it as closer. However, this information only allows the observer to create a “ranking” of relative nearness. The presence of monocular ambient occlusions consists of the object’s texture and geometry. These phenomena are able to reduce the depth perception latency both in natural and artificial stimuli.
Binocular Cues
[Stereopsis, or Retinal (Binocular) Disparity, or Binocular Parallax]
Our senses are bombarded by countless stimuli at any every second of time, yet we only perceive a select few of them clearly. For instance, while talking to your classmate, you might not be aware of the cracking sound the fan above your head is making or the scribbling of pen another classmate is doing. Though we get constant input into your senses, especially your ears, we attend or focus only on a certain stimuli (like talking to your classmate). The term given to this perceptual process of selecting only a few or certain stimuli or input for inclusion in our conscious awareness is known as
Attention
Is the cognitive process of selectively concentrating on one aspect of the environment while ignoring other things. It is the process through which we select stimuli which we want to register into our awareness. It involves selecting certain stimuli for processing and to can- celling out of stimuli that we don’t intend to register in our awareness.
Attention
Attention is a conative act, and so needs the
presence of volition.
Behind any act of ‘attention’ there is a motive, incentive goal, purpose or interest. ‘Interest is latent attention and attention is interest in action. Stronger the purpose, the more intense the attention.
Purposiveness
Attention is selective activity of the mind. It is focusing of consciousness on an idea, or object of thought. When we focus cur torch on any object, the vision becomes clearer, otherwise with diffu- sion of light over a vast area, the object will be presented dim. In the same manner, we focus our mind to one specific object.
Selection
The first fundamental basis is the instincts.
Basis of Selection
According to the principle of selection, we might suppose that a person attends to only one thing at a time. But we do observe persons doing at least two things at a time.
Shift
Every act of attention has a corresponding motor adjustment of the body. A candidate in the examination hall attending to the question paper sits in a particular posture. The thinking scientist contracts his forehead. The spectator at the sports stadium jumps up at an interesting situation.
Attending and Motor Adjustment
Determinants of Attention
Attention and Processing of Information, Central Bottleneck Theory
as the processing in which an individual tries to pay attention to 2 or more inputs and picking out information from both of them parallely. Another example would include listening music while doing a mathematical numerical.
parallel processing
In the case of the party scenario, you would actually notice that you were paying much more attention to one of the conversation than the other at a time. i.e. attending to one set of inputs than another.
Serial Processing
is the process of paying attention to two or more tasks. As the term suggests, it is ‘dividing’ attention to more than one task.
Divided attention
Theories on Divided Attention
Central Capacity Theories, Multiple Resource Theory, Automatic and Controlled Processing, Instance Theory
can be allocated to many activities. This capacity is limited which means that performance of multiple tasks depends on the demands of each individual task. Decrement in task performance is observed when the demands on the tasks exceed the available attention resources.
Central Capacity Theories
This theory focuses on the idea that when two tasks are similar, they compete for the same resources which lead to decline in task performance. Whereas when the tasks are dissimilar they draw upon different resources. So, there is decreased interference and better task performance.
Multiple Resource Theory
In 1977, Shiffrin and Schneider gave the concept of automatic and controlled processing. As the term suggests, automatic processing refers to the processing that is not available to our conscious- ness and develops through practice. It is fast and requires fewer attentional processes. Where on one hand, automatic processing has no capacity limits. On the other hand, controlled processing is of limited capacity. It requires more attentional resources and is often used in unknown situations.
Automatic and Controlled Processing
Logan said that “automaticity is memory retrieval: performance is automatic when it is based on a single step direct access retrieval of past solutions from memory.” This theory was developed by Logan in 1988 and it focuses on how automaticity develops through practice. It states that practice with a stimulus leads to storage of information of that stimulus and there are separate memory traces for each stimulus. There is an increase in knowledge which helps in retrieval of information and hence, automaticity develops through practice.
Instance Theory
is the process of directing our awareness to relevant stimuli while ignoring irrelevant stimuli in the environment. This is an important process as there is a limit to how much information can be processed at a given time, and selective attention allows us to tune out insignificant details and focus on what is important. This limited capacity for paying attention has been conceptualized as a bottleneck, which restricts the flow of information. The narrower the bottle- neck, the lower the rate of flow.
Selective attention
Theories of Selective Attention
Visual Attention, Selective Auditory Attention, In Attentional Blindness
Operates on two stages:
Initial stage: Attention is scattered over the entire visual field.
Secondary stage: Attention is directed towards specific inputs, and cognitive functioning is serial.
Visual Attention
Ability to focus on specific auditory stimuli, like a voice, while ignoring other background noises.
Selective Auditory Attention
Unattended stimuli register in the nervous system but do not enter conscious experience.
In Attentional Blindness
Environmental and Personal Factors in Attention
Stimulus Characteristics, Personal Factors
- Intensity, novelty, movement, contrast, and repetition are key attractors of attention.
- Sexually oriented stimuli are particularly attention-grabbing.
Stimulus Characteristics
-Motives and interests act as filters influencing which environmental stimuli are noticed.
-Example: A graphologist’s interest in handwriting samples.
Personal Factors
-Challenges the idea of the filter as a decisive factor in conscious sensory input recognition.
-Suggests an early-selection filter that attenuates unattended information.
Unattended stimuli must exceed a threshold to be acknowledged.
-Semantic characteristics of stimuli serve as their own filter.
-Example: Hearing one’s own name triggers attention shift despite surrounding noise.
Filter Attenuation Theory by Anne Treisman
-Refers to the minimum level necessary for stimuli to gain conscious awareness.
-Lower thresholds increase the likelihood of recognition after attenuation.
-Example: One’s own name has a lower recognition threshold compared to less significant information.
Recognition Threshold
Threshold Affecters
Context and Priming, Subjective Importance, Hierarchy of Analyzers
-Context lowers the identification threshold by creating an expectant environment.
-Acts as a priming agent, making input more accessible and reducing its threshold.
-Example: The word ‘round’ is easily recognized in the statement “the table is round” due to context.
Context and Priming
-Words with subjective significance have a lower recognition threshold.
-Personal relevance increases the likelihood of stimulus processing.
-Example: Hearing “your house is on fire” prompts immediate attention.
-Stereotype and taboo words are recognized more easily than common words.
Subjective Importance
-Manages information processing and attenuates unattended information.
-Protects against sensory overload by scrutinizing overwhelming input.
-Allows for complete processing when the load is manageable; prioritizes relevant stimuli when the load is high.
Hierarchy of Analyzers
